1. Field of the Invention
The present invention relates to a capacitive touch panel, more particularly to a touch position detector of a capacitive touch panel and a method for detecting the touch position.
2. Background of the Invention
Nowadays, touch panel has been widely used in electronic device such as personal computer and mobile phone. As a kind of touch panel, capacitive touch panel has been used more widely.
The conventional capacitive touch panel includes a plurality of capacitive sensors, each of which has a basic capacitance. When an object, such as a finger, is touching on the capacitive touch panel, the capacitance of the capacitive sensor located at the touch position is changed. Then the capacitances of the capacitive sensors are measured and converted to digital signals by an analog/digital converter (ADC). So the touch position is detected according to the change of the capacitance. However, the basic capacitance is usually much more than the change of the capacitance, resulting in the basic capacitance can't be correctly compensated and be precisely read after being converted by the ADC. When the capacitances of the capacitive sensors are not uniform, the ADC will have seriously direct current (DC) shifts and different signals which make the touch position is hard to detect.